Solenoid valve question..

[olly_k]

Ok folks, got an idea for a project, and on a bit of a budget. Basically I need some solenoid water valves (12, 24v but no greater) that I will use to control the flow of water to fill a and empty a tank. I have found this here

http://www.ebay.co.uk/itm/DC12V-Mag...id=100005&rk=2&rkt=6&mehot=lo&sd=222145237265

Just wondering if it will work in reverse? If not are there any alternatives that are fairly cheap?

Thanks.

 

[bernardgreen]

Just wondering if it will work in reverse?

What do you mean by "in reverse" ?

If you mean water flowing in reverse then most likely not. In many of these valves the solenoid opens a small pilot valve which allows incomng water pressure to reach and operate a diaphram which controls the main valve, this type will not work in reverse.

 

[Scotts]

i suppose if you fitted one to the inlet and one to the outlet of the tank, depending on size of tank should create enough head of pressure to supply an outlet flow, height of the tank and where you place the outlet valve which will determine the outlet pressure.

 

[stem]

Just wondering if it will work in reverse?

On the other hand.... if by 'work in reverse' you mean that it would be normally open, and then closes when 12V is applied, then the answer is no. However you could incorporate a relay in the switching circuit to allow it to function like that.

 

[muggles]

Give us a bit more to go on

Solenoids that power closed and spring open are available if that's what you're after? What are you trying to achieve?

 

[Mikefromlondon]

Most solenoid valves are designed to be fail safe, that means they are shut and only open when energised with power. But that is not to say that normally open valves are not available as special since that could be a fail safe criteria for certain applications.

On many solenoid valves there is an arrow to determine flow direction, but they can still be used on low pressure systems either way, a high pressure system could leak through if connected against the flow direction, as pressure itself helps seal the valve seat firmly, a reverse pressure could lift the valve seat and leak.

 

[Agile]

Most of those types of valves only work in one direction.

Because of their servo action many need a minimum pressure to open.

In an open tank it is quite likely they would not open to empty the tank for this reason.

Tony

 

[olly_k]

ok folks, I should explain more.. But regardless I have realised that the direction doesn't matter, as I will need an extra sol valve for empty anyway! (Doh!) However I do hope such a valve will work with low pressure as it will rely on Siphon alone!

So this is for my fish tank. We have recently moved in to a new rented house, and the tank is now placed within the dining room. In my old house to do a water a change I would run a hose from the kitchen and prime with water from the tap, then move the hose out the back door and let the tank drain to required depth using siphon. Problem with this it was messy and required a certain amount of coordination and moving a water source around while potentially emptying the tank all over the place!

Once the siphon was going I could walk away and do something else until the water level was below the pipe in the tank, and of course everything would automatically stop.

So, new place has a cellar, which will be ideal to drop a pipe in to for water removal, and I am good at electronics, so the attached image is my solution:

*Waist is the drain with the option of storage for garden plant watering...
*Doser is a peristaltic pump to does with dechlorinate
the second unmarked sol valve is there as redundancy.
*Optional fill rate I wont bother with but if I do it would simply be two valves, with two ball valves set at two different flow rates. A combination allows for three fill rates to be achieved.

Out of interest, what would be the best solution for the upper valve to allow me to purge the pipe of water? It is designed to let air in so the pipe can be cleared of water without emptying the tank, but would ideally include a one way valve to prevent water escaping..

Any advice regards the plumbing will be appreciated!

Thanks,

Olly.

 

[bernardgreen]

Might be less expensive to use a pump to take water from the tank and a standard washing machine solenoid valve to add fresh water to the tank.

 

[Dan Robinson]

Jesus. Talk about over thinking....

http://www.halfords.com/workshop-to...N-18Vt6rbkVwM4zz7FDYlXf5eu1BOeBR7jRoCF0Xw_wcB

 

[flameport]

What is shown in the diagram could not possibly comply with water regulations, as there is an outlet below the water level of the fish tank connected to the mains water supply.
To make things worse, you are actively encouraging water to be siphoned out of the tank.

 

[Mikefromlondon]

In order to comply you need to fill your tank from the top with a clear break between your filling valve spout and the maximum likely water level and the gap should be at least an inch roughly. Filler valve should also be a one way, similar to used on CH for added safety, but it doesn't have to be as in loft water tanks that uses ball float valves. The minimum gap ensures there should be no possibility of syphoning or reverse flow occurring. So you do not use a common pipe for both filling and draining.
RS Components do a two way solenoid for about 15 odd quid, minimum pressure 0.2bar http://uk.rs-online.com/web/p/solen...3743D3334322D303233267374613D3033343230323326

Edit: The valve you pointed us on your link will work just as well, and is much cheaper, RS have always been more expensive, but are reliable.

 

[AGAS]

you definitely think to much mate , as above has shown . are you retired have you got a lot of time on your hands , as said you've got to think about the water regs ,well .... you don't have to i suppose i just imagine tupperware with wires everywhere for your goldfish

 

[Mikefromlondon]

May be OP's tank is so huge, that cannot be emptied easily using a few buckets, manually.

 

[olly_k]

To all those who are saying I am overthinking f@ck off and use some imagination! This is the sort of thing I do at work and I also happen to enjoy the challange of projects like better than going to the pub or spending my life flaming people on forums lol
yeah it is a big tank and I could do without the hassle and possibility of spilling water on the wooden floor etc etc.

For those who have given me constructive feedback thank you. Yes RS is expensive but at least items are likely to be reliable as you say.